Fuel supply component cleaning system

ABSTRACT

A method is provided for operating a regeneration assembly to regenerate a filter assembly during a regeneration cycle, and for supplying fuel to at least one fuel injector unit associated with the regeneration assembly during the regeneration cycle. The method includes dispensing a cleaning substance into a fluid flow path associated with the regeneration assembly during a cleaning cycle. The method further includes directing the cleaning substance through the at least one fuel injector unit during the cleaning cycle.

TECHNICAL FIELD

The present disclosure is directed to a fuel supply component cleaningsystem and, more particularly, to a system and method for cleaning afuel injector unit for a regeneration assembly.

BACKGROUND

Engines, including diesel engines, gasoline engines, natural gasengines, and other engines known in the art, may exhaust a complexmixture of emissions. The emissions may include both gaseous and solidmaterial, such as, for example, particulate matter. Particulate mattermay include ash and unburned carbon particles generally referred to assoot.

Environmental concerns have resulted in the development of systems totreat engine exhaust. Some of these systems may employ exhaust treatmentdevices, such as particulate filters, to remove particulate matter fromthe exhaust flow. A particulate filter may include filter materialdesigned to capture particulate matter. After an extended period of use,however, the filter material may become partially saturated withparticulate matter, such as soot. This partial saturation may hinder theability of the particulate filter to remove particulates from theexhaust flow.

The collected particulate matter may be removed from the filter materialthrough a process called regeneration. A particulate filter may beregenerated by increasing the temperature of the filter material and theparticulate matter in the filter material above the combustiontemperature of the particulate matter. For regeneration to occur, oxygenmust be available to facilitate oxidation of the soot. The increase intemperature results in oxidation of the collected particulate matter.The chemical reaction is C+0₂→CO₂.

The increase in temperature to support oxidation of soot may beeffectuated by a regeneration assembly including a combustion chamber.The combustion chamber may require a fuel injector unit for fuel that isto be ignited within the combustion chamber. In addition, a fuel supplycircuit, including a flow passage or flow passages, may be provided fordelivering the fuel from a source to the fuel injector unit. Duringregeneration, fuel may flow through the fuel supply circuit and the fuelinjector unit to support combustion within the regeneration assembly.

After a regeneration event or cycle, the supply of fuel to theregeneration assembly may be shut off. However, fuel may remain withinthe fuel supply circuit and the fuel injector unit. The fuel injectorunit and/or fuel supply circuit may be subjected to a build-up ofsubstances that may be contained within or derived from fuel remainingwithin the fuel injector unit and/or fuel supply circuit. For example,when fuel remains within a fuel injector unit and/or fuel supply circuitfor a time, the environment is conducive to a build-up of carbondeposits. Such a build-up of substances may inhibit proper operation ofthe fuel injector unit and/or fuel supply circuit, and may adverselyaffect performance of the regeneration assembly.

Nozzle purging of fuel injector units may be effective in removing fuelfrom a fuel injector unit. However, residual fuel may remain in the fuelsupply circuit after regeneration, and may leak toward the fuel injectorunit. Moreover, valves in the fuel supply circuit may be subject toseepage or leakage, resulting in fuel leaking to the fuel injector unitafter nozzle purging. As a result, the fuel injector unit may be exposedto contact with non-flowing fuel for a time sufficient to cause abuild-up of deposits which may adversely affect fuel delivery to theregeneration assembly. Such a build-up may require fuel injector unitremoval for cleaning, or replacement, and resulting downtime.

One system for purging a fuel injector nozzle is disclosed in U.S. Pat.No. 4,987,738, issued to Lopez-Crevillen et al. on Jan. 29, 1991 (“the'738 patent”). The '738 patent discloses a filter for exhaust gases, anda burner that may regenerate the filter. In the '738 patent, a fuel pumpdirects fuel to a fuel injector nozzle which injects fuel into theburner during regeneration. Following a regeneration event, anElectronic Control Module (ECM) controls a solenoid valve to shut offfuel to the fuel pump, and direct purge air from an air pump, throughthe fuel pump, and through the fuel injector nozzle. Purge air continuesto flow through the fuel pump and the fuel injector nozzle until asubsequent regeneration event to prevent soot build-up on the nozzle.

While the system of the '738 patent contemplates purging a fuel pump andfuel injector nozzle, no provision is made for dispensing a cleaningsubstance to clean the fuel injection nozzle. Rather, the '738 patentdiscloses that purge air continues to flow through the fuel pump and thefuel injection nozzle following a regeneration event until a subsequentregeneration event.

The purging system of the '738 patent may be inefficient and potentiallywasteful of fuel since the air pump must operate continuously betweenregeneration events, and since fuel may persistently leak past thesolenoid valve and be forced into the burner. The energy necessary tocontinuously drive the air pump, coupled with the potential waste offuel that may leak past the solenoid valve, may result in unacceptableinefficiency. Further, air alone may purge some of the liquid fuel fromnozzle components, but may not remove all fuel from the nozzlecomponents, and may not clean nozzle components by removing the build-upof deposits. As a result, build-up of deposits on nozzle components mayremain a concern. In addition, the large wetted area to be purged in thesystem of the '738 patent coupled with constantly purging small amountsof fuel to the injection device may even increase the chance of carbongrowth at the site of the injection device.

The disclosed cleaning system and method are directed toward overcomingone or more of the problems set forth above.

SUMMARY OF THE INVENTION

In one exemplary embodiment of the present disclosure, a methodcomprises operating a regeneration assembly to regenerate a filterassembly during a regeneration cycle, and supplying fuel to at least onefuel injector unit associated with the regeneration assembly during theregeneration cycle. The method includes dispensing a cleaning substanceinto a fluid flow path associated with the regeneration assembly duringa cleaning cycle. The method further includes directing the cleaningsubstance through the at least one fuel injector unit during thecleaning cycle.

In another exemplary embodiment of the present disclosure, a systemcomprises a regeneration assembly configured to regenerate a filterassembly during a regeneration cycle, and a combustion chamberassociated with the regeneration assembly. The system includes a fuelinjector unit for injecting fuel into the combustion chamber during theregeneration cycle. The system also includes a gas flow path configuredto communicate with the fuel injector unit. The system also includes agas source for selectively supplying gas through the gas flow path tothe fuel injector unit. The system further includes an assembly fordispensing a cleaning substance into the gas flow path for cleaning thefuel injector unit during a cleaning cycle.

In still another exemplary embodiment of the present disclosure, amachine comprises an engine system including an exhaust flow path. Themachine includes a filter assembly in the exhaust flow path. The machinealso includes a regeneration assembly proximate the exhaust flow pathupstream of the filter assembly, the regeneration assembly including acombustion chamber and configured to regenerate the filter assemblyduring a regeneration cycle. The machine also includes at least one fuelsupply circuit and at least one fuel injector unit associated with thecombustion chamber. The machine further includes an assembly configuredto dispense a cleaning substance to the at least one fuel injector unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic and schematic illustration of a machineincluding a system according to an exemplary embodiment of the presentdisclosure, and illustrating a valve in one possible setting fordirecting fluid flow.

FIG. 2 is a diagrammatic and schematic illustration of a machineincluding a system according to an exemplary embodiment of the presentdisclosure, and illustrating a valve in another possible setting fordirecting fluid flow.

FIG. 3 is a diagrammatic illustration of a cleaning system according toan exemplary embodiment of the present disclosure.

FIG. 4 is a diagrammatic illustration of a cleaning system according toanother exemplary embodiment of the present disclosure.

FIG. 5 is a chart showing a purging control strategy.

DETAILED DESCRIPTION

A machine 10, in which exemplary disclosed embodiments may beimplemented, is diagrammatically represented in FIG. 1 and in FIG. 2.Machine 10 may be any of various machines, including an on-highwaytruck, an off-highway haulage unit, an excavating machine, a materialhandling machine, a stationary power generating machine, any of variousheavy equipment machines, or any other machine which may benefit fromimplementation of embodiments according to the disclosure.

An engine system 12 may be associated with machine 10. Engine system 12may include an engine 14 and various subsystems generally associatedwith an engine. Engine 14 may be any one of various types of engines,such as, a gasoline fueled engine, a diesel fueled engine, or a gasfueled engine. Engine 14 may require, among other things, an air intakesystem 16 and an exhaust system 18, both diagrammatically illustrated inFIG. 1. Air intake system 16 may include various unillustrated intakesystem components generally associated with engine air intake systems.For example, air intake system 16 may include an opening for intake air,an air filter for filtering the intake air, an intake manifold, and anintake air flow passage for directing intake air from an intake openingto the intake manifold.

Exhaust system 18 also may include various unillustrated exhaust systemcomponents generally associated with an exhaust system. For example,exhaust system 18 may include an exhaust manifold, and one or moreenergy extracting devices, such as turbines, which may in turn drive oneor more air pressurizing devices, such as compressors suitably situatedin the air intake system for compressing intake air. Additionally,various components particularly designed to control exhaust emissionsmay be associated with the exhaust system.

In order to better illustrate the various components of a disclosedembodiment, exhaust system 18 is illustrated as discontinuous. It willbe understood, however, that exhaust system 18 extends continuously froma location at which it is connected to engine 14, for example at anexhaust manifold, to a position where exhaust is ultimately emitted tothe environment. Between the location at which exhaust system 18 isconnected to engine 14 and the location at which exhaust is emitted tothe environment, engine exhaust may undergo various treatment processes,may drive energy extracting devices, and/or may be diverted for mixingwith engine combustion air.

A fuel supply system 20 may supply a suitable fuel to engine 14. Fuelsupply system 20 may include a fuel source 22, such as a tank, one ormore suitable fuel pumps, such as fuel pump 24, and various fuel flowpassages, valves, and elements generally associated with an engine fuelsystem. Fuel supply system 20 may include a fuel manifold, or fuel rail,and one or more engine fuel injector units, all not shown. Fuel may bedirected to engine 14 via suitable fuel flow passages designated 26.Fuel may be directed from engine 14 back to tank 22 via a suitablereturn line 28.

An aftertreatment device, such as filter assembly 30, may be provided inthe exhaust flow path 32. Filter assembly 30 may include, for example, adiesel particulate filter which may remove soot and other particulatesfrom exhaust gases. As filter assembly 30 accumulates removed soot andother particulates, filter assembly 30 may tend to become less efficientin its intended purpose, and/or may tend to restrict the flow of exhaustgases. One or more suitable diagnostic devices, such as diagnosticdevice 34, for example, may monitor one or more parameters (e.g.,temperature, pressure, etc.) associated with the accumulation of sootand particulates in filter assembly 30. Diagnostic device 34 maycommunicate with a controller 82 via a suitable communication lineillustrated by a dotted line in FIGS. 1 and 2. Downstream of filterassembly 30, a portion of filtered exhaust gas may be diverted to aclean exhaust injection system, diagrammatically indicated at 31, formixing with combustion air for engine 14, for example.

A regeneration assembly 36 may be located upstream of filter assembly30, and generally proximate thereto, in or proximate to the exhaust flowpath 32. Regeneration assembly 36 may include a suitable combustionchamber, not separately shown, into which fuel and air may be introducedand ignited by a suitable ignition device, such as igniter 38.Alternatively, fuel may be supplied to catalyst that permitsautoignition. Heat generated by combustion within the regenerationassembly 36 may raise exhaust gases to a temperature sufficient toconsume soot accumulated in proximately situated filter assembly 30.

Referring to FIGS. 1 and 2, the general flow of exhaust through exhaustflow path 32, and the arrangement of elements associated withregeneration assembly 36, are diagrammatically illustrated. Fuel forcombustion within regeneration assembly 36 may be introduced via atleast one fuel injector unit designated 40 and diagrammaticallyillustrated. It will be understood that fuel injector unit 40 may be anysuitable injector or nozzle designed for and capable of injecting fuelinto the combustion chamber of regeneration assembly 36. It will also beunderstood that there may be plural injector units, and that injectorunit 40 may include plural injectors or nozzles.

A source of combustion air may be delivered to regeneration assembly 36via a combustion air flow passage 42. Delivery of combustion air viaflow passage 42 may be suitably controlled with a valve unit 44.Combustion air may be derived directly from ambient, may be derived fromair intake system 16 of engine 14, may be derived from a suitablecompressor, and may include a mixture of air and exhaust gases derivedfrom exhaust system 18, for example via clean gas injection system 31.

One or more suitable diagnostic devices, such as diagnostic device 46,may be associated with regeneration assembly 36 to monitor one or moreparameter associated with the operation of regeneration assembly 36. Forexample, diagnostic device 46 may monitor temperature, pressure, orbuild-up of particulates. Diagnostic device 46 may communicate withcontroller 82 via a suitable communication line.

Fuel injector unit 40 may be a component of a fuel supply circuit,generally designated 48. Fuel supply circuit 48 may be an independentfuel delivery system, or, as illustrated in the exemplary embodiment ofFIGS. 1 and 2, fuel supply circuit 48 may be integrated with the enginefuel supply system 20. In the exemplary embodiment of FIGS. 1 and 2,fuel for regeneration assembly 36 is supplied from fuel source 22 by oneor more fuel pumps, such as fuel pump 24, via fuel flow passage 26. Fuelflow passage 26 may deliver fuel through an enable valve 50, throughsuitable fuel passages in fuel supply circuit 48, and to fuel injectorunit 40.

Within fuel supply circuit 48, enable valve 50 may be arranged tofacilitate delivery of fuel to regeneration assembly 36. In theexemplary embodiment illustrated in FIG. 1, enable valve 50 may alsofacilitate delivery of fuel to engine 14. Enable valve 50 may be anytype of valve capable of facilitating fuel delivery to regenerationassembly 36, or to both regeneration assembly 36 and other machineelements, such as engine 14. For example, enable valve 50 may be a 4-wayvalve, partially illustrated in FIG. 1.

Referring to FIG. 1, enable valve 50 is illustrated in a positionpermitting fuel to flow through fuel supply circuit 48 towardregeneration assembly 36. Thus, in the enable valve 50 positionillustrated in FIG. 1, fuel may flow from fuel source 22 and bedelivered by fuel pump 24 via fuel flow passage 26 through enable valve50 and fuel supply circuit 48 to regeneration assembly 36. As alsoillustrated in FIG. 1, fuel may flow from fuel source 22 and bedelivered by fuel pump 24 via fuel flow passage 26 and check valveassembly 52 to engine 14.

Referring now to FIG. 2, which is essentially identical to FIG. 1 in allrespects except that FIG. 2 illustrates enable valve in a positioninhibiting the flow of fuel to regeneration assembly 36, and directingthe flow of fuel to engine 14. Check valve assembly 52 is configured toinhibit the flow of fuel in a reverse direction, while fuel passesthrough enable valve 50 to engine 14. While the position of enable valve50 illustrated in FIG. 2 inhibits the flow of fuel to regenerationassembly 36, it permits fuel supply circuit 48 to be connected to fuelreturn flow passage 54. Fuel return flow passage 54 may merge with fuelreturn line 28.

Fuel supply circuit 48 may include one or more on/off valves. Forexample, in the exemplary embodiment illustrated in FIGS. 1 and 2, mainon/off valve 56 and pilot on/off valve 58 are illustrated. Main andpilot on/off valves 56 and 58 may be any of various valves capable ofsuitably moving between an open position and a closed position such thatflow of fluid through the valves is either on or off. For example, mainand pilot on/off valves 56 and 58 may be suitable pulse width modulated(PWM) valves.

In FIGS. 1 and 2, main on/off valve 56 may be within a main flow passage60, and pilot on/off valve 58 may be within a pilot flow passage 62.Pilot flow passage 62 and pilot on/off valve 58 may facilitate thedelivery of a pilot fuel injection by fuel injector unit 40 to assist ininitiating combustion, for example. Main flow passage 60 and main on/offvalve 56 may facilitate the delivery of a main fuel injection by fuelinjector unit 40 to sustain combustion, for example. Within main flowpassage 60, a suitable diagnostic device 64 may be provided to monitor asuitable parameter in main flow passage 60 such as, for example,pressure. Similarly, within pilot flow passage 62, a suitable diagnosticdevice 66 may be provided to monitor a suitable parameter in pilot flowpassage 62 such as, for example, pressure. Main and pilot on/off valves56, 58, and both diagnostic devices 64, 66, may communicate withcontroller 82 via a suitable communication line.

Regeneration assembly 36 may operate intermittently in regenerationcycles to perform regeneration of filter assembly 30. Betweenregeneration cycles, fuel may lie within components of the fuel supplycircuit 48, such as fuel flow passages and injector unit 40. Inaccordance with an exemplary disclosed embodiment, injector unit 40and/or fuel supply circuit 48 may be purged of fuel. Purging of injectorunit 40 and/or fuel supply circuit 48 may be accomplished by supplyinggas, such as air, to the injector unit 40 and/or to fuel supply circuit48.

In the exemplary embodiment illustrated in FIGS. 1 and 2, a gas source68 may be provided. Gas source 68 may be any suitable gas source. Forexample, gas source 68 may be an air pump, the engine air intake systemof a machine, such as machine 10, associated with the regenerationassembly, a compressor, or any other suitable gas source. Gas source 68may include the compressor of an associated machine, such as machine 10,otherwise employed to delivered compressed air to machine components.For example, gas source 68 may be the brake compressor of a machine airbrake system, such as the air brake system of an on-highway truck. Airsource 68 may be an air pump or compressor driven by the engine of anassociated machine or driven by a separate motor. Gas source 68 mayserve as a source of purge air to facilitate purging fuel injector unit40 and/or fuel supply circuit 48.

Gas source 68 may deliver purge air to fuel injector unit 40 and/or fuelsupply circuit 48 via gas flow path 70. Downstream of gas source 68, andwithin gas flow path 70, a suitable filter/accumulator 72 may beprovided. Gas flow path 70 may make suitable connection to fuel injectorunit 40 or fuel supply circuit 48. In the exemplary embodimentillustrated in FIGS. 1 and 2, gas flow path 70 may comprise branches 74and 76 which may connect, respectively, to main flow passage 60 andpilot flow passage 62 proximate regeneration assembly 36 and fuelinjector unit 40. Check valves 78 and 80 may be provided, respectively,in branches 74 and 76 to inhibit the flow of fuel into gas flow path 70.

Filter/accumulator 72 may remove undesired contaminants from purge airor gas and enable delivery of relatively uncontaminated air or gas tofuel injector unit 40 and/or fuel supply circuit 48. In addition, filteraccumulator 72 may add volume to gas flow path 70 and serve as apressure accumulator when gas source 68 is enabled. The volume offilter/accumulator 72 may be sized as a function of the volume of fuelsupply circuit 48. For example, in an exemplary embodiment, the volumeof filter/accumulator 72 may be sized to be approximately twice thevolume of fuel supply circuit 48. Suitably sizing filter/accumulator 72relative to fuel supply circuit 48 may permit pressure to buildsufficiently within fuel supply circuit 48 during a purging cycle.

Various machine components, including regeneration assembly 36, filterassembly 30, fuel supply circuit 48, and components associated with thesupply of purge gas, may be monitored and controlled by a suitablecontroller, such as controller 82. In the exemplary embodimentillustrated in FIGS. 1 and 2, controller 82 may be connected by suitablelines (illustrated as dotted lines) to the various diagnostic devices,valves, and other components to be monitored and/or controlled.Controller 82 may include a computer supplied with suitable algorithms,programs, and/or control strategies designed to effectuate efficientoperation of machine and system components.

An exemplary embodiment suitable for cleaning fuel supply and fuelinjecting components is schematically and diagrammatically illustratedin FIG. 3. FIG. 3 illustrates a cleaning system 84. Associated withcleaning system 84 is a regeneration assembly 36′. Regeneration assembly36′ may be the same as or similar to the regeneration assembly 36 in theexemplary embodiment of FIGS. 1 and 2. In other words, regenerationassembly 36′ may be associated with an exhaust system in a suitablemachine, and may include a combustion chamber and associated fuel supplycomponents such as a fuel supply circuit and one or more fuel injectorunits as described in connection with the embodiment of FIGS. 1 and 2.

Cleaning system 84 may be employed where circumstances dictate that fuelsupply components, such as a fuel supply circuit and/or one or more fuelinjector units, may benefit from exposure to a suitable cleaningsubstance, such as cleaning fluid, solvent, or solution. Cleaning system84 may include an assembly 85 that may include a suitable service tool86 for delivering a quantity of a suitable cleaning fluid, solvent, orsolution to fuel supply components. FIG. 3 illustrates gas source 68′,gas flow path 70′, and filter/accumulator 72′, all of which may beidentical to or similar to the gas source 68, gas flow path 70, andfilter 72 described in connection with the embodiment of FIGS. 1 and 2.

Connected to gas flow path 70′, in assembly 85, is a suitable cleaningport 88. Cleaning port 88 may include a short flow passage, such as flowpassage 90, and a check valve, such as check valve 92. Check valve 92may facilitate one-way flow of cleaning fluid into gas flow path 70′.Service tool 86 may be any suitable tool enabling the introduction of asuitable cleaning fluid into gas flow path 70′. For example, in theexemplary embodiment illustrated in FIG. 3, service tool 86 may be asyringe capable of dispensing a measured amount of cleaning fluid undermanual control by an operator. It will be understood that service tool86 may include other types of devices or instruments capable ofdispensing cleaning fluid. It will also be understood that service tool86 may be designed to dispense cleaning fluid under manual control, orby control mechanisms within the service tool.

A suitable pressure monitoring device such as a pressure gauge 94 may beemployed to ascertain pressure within gas flow path 70′. Pressure gauge94 may be suitably coupled to a gauge port 96 which may be connected togas flow path 70′ via a short flow passage, such as flow passage 98. Acheck valve 100 may be located in gas flow path 70′ upstream of thelocation of introduction of cleaning fluid into gas flow path 70′. Checkvalve 100 may effectively preclude the flow of cleaning fluid in adirection toward filter 72′ and gas source 68′.

Another exemplary embodiment suitable for cleaning fuel supply and fuelinjecting components is schematically and diagrammatically illustratedin FIG. 4. FIG. 4 illustrates a cleaning system 102. Associated withcleaning system 102 is a regeneration assembly 36″. Regenerationassembly 36″ may be the same as or similar to the regenerationassemblies 36 and 36′ in the exemplary embodiments of FIGS. 1, 2, and 3.In other words, regeneration assembly 36″ may be associated with anexhaust system in a suitable machine, and may include a combustionchamber and associated fuel supply components such as a fuel supplycircuit and one or more fuel injector units.

In a manner similar to cleaning system 84 in the exemplary embodimentillustrated in FIG. 3, cleaning system 102 in the exemplary embodimentof FIG. 4 may be employed where circumstances dictate that fuel supplycomponents such as a fuel supply circuit and/or one or more fuelinjector units may benefit from exposure to a suitable cleaningsubstance, such as cleaning fluid, solvent, or solution. Cleaning system102 may include an assembly 103 that may include a suitable supplycontainer 104 for delivering a quantity of a suitable cleaning substanceto the fuel supply components. In the embodiment of FIG. 4, gas source68″, gas flow path 70″, and filter/accumulator 72″ may be identical toor similar to the gas source 68, 68′, gas flow path 70, 70′, andfilter/accumulator 72, 72′ described in connection with the embodimentsof FIGS. 1, 2, and 3.

A suitable metering valve 106 may be associated with supply container104. Supply container 104 and metering valve 106 may be connected to gasflow path 70″ by a short flow passage, such as flow passage 108, whichmay include a suitable check valve, such as check valve 110. Check valve110 may facilitate one-way flow of cleaning fluid into gas flow path70″. Supply container 104 may be any suitable supply container enablingthe introduction of a suitable cleaning substance into gas flow path70″. For example, in the exemplary embodiment illustrated in FIG. 4,supply container 104 may be a pressure container configured to containcleaning fluid under pressure. Supply container 104 may be designed tobe readily replaced, for example, for one-time use, and may be designedto contain a measured quantity of cleaning fluid. For example, supplycontainer 104 may be a pressure container configured and sized to hold18 ounces of liquid.

A check valve 112 may be located in gas flow path 70″ upstream of thelocation of introduction of cleaning fluid into gas flow-path 70″. Checkvalve 112 may effectively preclude the flow of cleaning fluid in adirection toward filter 72″ and gas source 68″.

In the exemplary embodiment illustrated in FIG. 4, the introduction ofcleaning fluid into gas flow path 70″ may be implemented under a controlstrategy. A suitable controller 82′, identical to or similar tocontroller 82 in the embodiment of FIGS. 1 and 2, may control theintroduction of cleaning fluid according to a timed control strategy, orin response to an indication that a fuel supply circuit and/or a fuelinjector unit may benefit from contact with cleaning fluid. One or morediagnostic devices, such as diagnostic device 114, may be associatedwith regeneration assembly 36″, and configured to monitor one or moreparameters indicative that a cleaning cycle may be beneficial. Forexample, diagnostic device 114 may monitor temperature and/or pressureeither within the regeneration assembly 36″ or in the fuel supplycircuit supplying fuel to the regeneration assembly 36″. Controller 82′may determine when cleaning supply container 104 is empty by countingthe number of cleaning events performed or by monitoring a suitablediagnostic device, for example. Data gathered and conditions sensed bydiagnostic device 114 may be relayed to controller 82′ via a suitablecommunication line.

Controller 82′ may be suitably connected to gas source 68″ and tometering valve 106 via suitable communication lines. Lines connectingcontroller 82′ to diagnostic device 114, gas source 68″, and meteringvalve 106 are indicated in FIG. 4 as dotted lines. Controller 82′ mayimplement various control strategies for cleaning fuel supply circuitcomponents. For example, controller 82′ may be suitably programmed toimplement a cleaning cycle after a predetermined number of regenerationcycles. For example only, controller 82′ could implement a cleaningcycle, including introduction of cleaning fluid, after ten regenerationcycles. In addition, controller 82′ could implement a cleaning cycleresponsive to feedback from diagnostic device 114 indicating that fuelsupply circuit components could benefit from a cleaning cycle regardlessof the number of regeneration cycles that have occurred.

Referring collectively to FIG. 3 and to FIG. 4, a cleaning cycle mayinclude a number of events. For example, prior to introduction ofcleaning fluid either by service tool 86 in the exemplary embodiment ofFIG. 3, or by supply container 104 in the exemplary embodiment of FIG.4, gas source 68′, 68″ may be activated to at least partially purge fuelfrom fuel supply circuit components including the fuel injector unitand/or the fuel supply circuit associated with regeneration assembly36″. In addition, subsequent to introduction of cleaning fluid in eitherof the exemplary embodiments of FIGS. 3 and 4, gas source 68′, 68″ maybe activated to at least partially purge cleaning fluid from gas flowpath 70′, 70″, as well as from the fuel injector unit and/or the fuelsupply circuit associated with regeneration assembly 36′, 36″

It should be understood that the exemplary embodiment of FIG. 3 may beassociated with and may be a component of the exemplary embodiment ofFIGS. 1 and 2. Similarly, the exemplary embodiment of FIG. 4 may beassociated with and may be a component of the exemplary embodiment ofFIGS. 1 and 2. In other words, the embodiments of FIGS. 1 and 2 on theone hand, and FIG. 3 and FIG. 4 on the other hand, are not mutuallyexclusive. Rather, the cleaning system illustrated in FIG. 3 or in FIG.4 may be employed to introduce cleaning fluid into the fuel supplycircuit components of the embodiment of FIGS. 1 and 2. Referring toFIGS. 1 and 2, for example, arrow 116 designates an exemplary locationalong gas flow path 70 at which assembly 85 including service tool 86and associated components 88, 90, and 92 of FIG. 3 could be convenientlyaccommodated. Similarly, assembly 103 including supply container 104,metering valve 106 and associated components 108 and 110 of FIG. 4likewise could be accommodated at the location designated by arrow 116.

INDUSTRIAL APPLICABILITY

The disclosed embodiments may be used to facilitate effective andefficient regeneration of a filter by a regeneration assembly, such asregeneration assembly 36, 36′, 36″. Filters which may be regenerated mayinclude any type of filters known in the art which are capable of beingregenerated, such as, for example, particulate filters useful inextracting pollutants from a flow of fluid. Such filters, and thus, theregeneration assembly 36, 36′, 36″, may be fluidly connected to anexhaust outlet of, for example, a diesel engine, gasoline engine, orother power source generating a flow of exhaust.

FIG. 5 illustrates a table 118 that may assist in understanding anexemplary strategy for purging fuel supply circuit components associatedwith a regeneration assembly 36, 36′, 36″ during a purging cycle. Table118 is illustrated with vertical columns A-G, to be explained more fullybelow, and horizontal rows corresponding to a sequence of events. FIG. 5is exemplary, and not limiting. Numerous and various control strategiesdesigned to extend fuel injector unit life and fuel supply circuit life,and extend the time between component cleaning and maintenance, arecontemplated within the scope of this disclosure.

Referring to FIG. 5 and table 118, column A designates a sequence ofevents. At event 0, a regeneration cycle is in progress, and fuel issupplied to the fuel supply circuit 48 and fuel injector unit 40,referring to the embodiment of FIGS. 1 and 2. As can be seen from columnD, the pump (referring to an embodiment of gas source 68) is off, and nopurging gas is flowing. Column E indicates that the PWM valve (referringto an embodiment of on/off valves 56, 58) is open, and column Gindicates that enable (enable valve 50) is on, both together indicatingthat fuel is flowing through fuel supply circuit 48 to fuel injectorunit 40. At the onset of a regeneration cycle, enable valve 50 may bemoved to the position illustrated in FIG. 1, permitting fuel to besupplied from fuel source 22 to the combustion chamber of regenerationassembly 36. Column F indicates that regeneration is in progress (i.e.,no purge, regeneration active).

The exemplary purging strategy indicated by table 118 illustratessixteen events numbered 1-16 in a purging cycle. Event 17 designates theend of the purging cycle. Event 1 occurs after a regeneration cycle attime 0. Pump (gas source) is off, PWM (on/off valve(s)) is closed, andenable (enable valve 50) is off. Enable off indicates that enable valve50 is in the position indicated in FIG. 2 wherein fuel supply circuit 48is connected to return line 54, and fuel pump 24 is not delivering fuelto fuel supply circuit 48. At the onset of a purging cycle, enable valve50 may be moved to the position indicated in FIG. 2 inhibiting fuel frombeing supplied from the fuel source 22 to the combustion chamber, andpermitting fuel to flow from the fuel supply circuit 48 toward the fuelsource 22. Event 1 may be of only a duration sufficient to achieve PWMclosed and enable off.

Event 2 may occur immediately after event 1. At event 2, pump (gassource) is on, indicating that purging gas is flowing into gas flow path70 and toward the connection of branches 74, 76 with main flow passage60 and pilot flow passage 62, referring to FIG. 2. During event 2,filter/accumulator 72 is charged to a suitable pressure as gas source 68is enabled. The pressure to which filter/accumulator 72 is charged maybe a function of the gas flow rate from source 68 and the flow area ofthe fuel injector unit 40. In other words, the pressure to whichfilter/accumulator 72 is charged may be greater with a greater flow ratefrom source 68, and greater with decreased flow area of fuel injectorunit 40.

It will be understood that, although filter/accumulator 72, 72′, 72′ hasbeen illustrated and described as a single element or component, it iscontemplated that the filter and the accumulator could, in fact, beseparate and distinct components. Accordingly, it will be understoodthat where reference is made to the filter/accumulator in a filteringcapacity, it could be a filter alone, and where reference is made to thefilter/accumulator in its accumulator capacity, it could be anaccumulator alone.

Column E indicates that PWM (main on/off valve 56 and pilot on/off valve58) is/are closed, and column G indicates that enable (enable valve 50)remains off, or in the position illustrated in FIG. 2. Because PWM isclosed, gas from gas source 68 cannot flow through fuel supply circuit48 toward enable valve 50 and fuel source 22. Instead, gas from gassource 68 is forced through fuel injector unit 40 and intervening supplylines to purge fuel injector unit 40 of fuel. The purged fuel may beforced into regeneration assembly 36. Column F indicates nozzle purge (afuel injection unit usually including one or more nozzles) during event2. Event 2 may be designated a fuel injector unit purging event and mayhave a duration of 30 seconds as indicated by column C.

Event 3 may occur immediately following event 2, with a duration of 15seconds. At event 3, pump remains on and enable remains off, but PWM isopen. PWM open, referring to FIG. 2, indicates that main on/off valve 56and pilot on/off valve 58 are open. Because PWM is open, gas from gassource 68 is permitted to flow through fuel supply circuit 48, throughenable valve 50, through return passage 54 and to fuel source 22. In theembodiment illustrated in FIGS. 1 and 2, a suitable check valve, such ascheck valve 55, may be disposed in return line 28 to inhibit gas and/orfuel flow through return line 28 and toward engine 14. Similarly, asuitable check valve, such as check valve 57, may be disposed in returnflow passage 54 to inhibit backflow from fuel return line 28 throughfuel supply circuit 48. Thus, during event 3, fuel within fuel injectorunit 40 is purged, and fuel supply circuit 48 (usually including one ormore fuel lines) is purged toward fuel source 22. Event 3 may bedesignated a fuel injector unit and fuel supply circuit purging event.

During event 3, filter/accumulator 72, discharges accumulated pressureat a rate that is a function of the flow area of fuel supply circuit 48and return flow passage 54 through which gas may flow (an area likelymuch greater than the flow area of fuel injector unit 40). During event3, the system pressure may drop rapidly as a function of the gas flowrate from gas source 68, particularly if the available flow rate isminimal, as may be the case where an electrically driven air pump is thegas source 68. Effectiveness of purging fuel back to fuel source 22 maybe increased by higher flow rates and reduced volume/cross-sectionalarea of the fuel supply and return lines (e.g., 60, 62, 54, etc.).

System design may be optimized to reduce fuel line size with a viewtoward improving the purging process. The accumulator volume withinfilter/accumulator 72 may provide an instantaneous flow rate exceedingavailable flow from, for example, an electrically operated pump, tofurther improve the purging process. Shortly after event 3 is initiated,system pressure rapidly drops after the filter/accumulator 72 isdischarged. According to an exemplary disclosed purging strategy, theprocess may be repeated.

Events 4, 6, 8, 10, 12, 14, and 16 are substantial repetitions of event2 wherein the fuel injector unit 40 (nozzle) is purged, but fuel supplycircuit 48 is not purged. Events 5, 9, and 11 are substantialrepetitions of event 3 wherein the fuel supply circuit 48 is purged backtoward fuel tank 22, while fuel injector unit 40 is simultaneouslypurged into regeneration assembly 36. Events 7, 13, and 15 aresubstantial repetitions of event 1 wherein pump (gas source 68) is off,PWM is closed, and enable is off, resulting in hiatus events where nopurging occurs. Under the exemplary control strategy of FIG. 5, apurging cycle would have a total duration 360 seconds, or six minutes.It is understood that this time duration is exemplary and not limiting.

The most suitable sequence of events within a purging cycle, and theduration of each event, may be empirically determined for a particularregeneration assembly fuel supply system. Fuel may not completely purgewith ease from the various spaces that may, in reality, occur in a fuelsystem. Bends and connections within fuel lines, the length of lines tobe purged, and spaces peculiar to valve and injector structure may workagainst adequate purging in a single purge event. Accordingly, a purgingstrategy wherein a purging cycle includes a sequence of timed events, asexemplified by the purging strategy illustrated in FIG. 5 and describedabove, may effectively and efficiently purge fuel injector unit 40and/or fuel supply circuit 48, extend fuel supply circuit componentlife, and reduce maintenance and downtime.

The exemplary control strategy illustrated by table 118 of FIG. 5 may beimplemented by controller 82, for example, referring to FIGS. 1 and 2.Controller 82 may include a suitable computer, programmed to implementthe control strategy of FIG. 5 as well as various other controlstrategies. FIGS. 1 and 2 include dotted lines between controller 22 andvarious components, such as gas source 68, main and pilot on/off valves56, 58, and diagnostic devices 34, 46, 64, and 66. Thus, controller 82may control gas source 68 (pump in FIG. 5), main and pilot on/off valves56, 58 (PWM in FIG. 5) and enable valve 50 (enable in FIG. 5), inimplementing a control strategy, such as the exemplary control strategyillustrated in FIG. 5.

Controller 82 may direct a purging cycle, including one or more events,after engine shutdown and/or shortly after engine start-up. In addition,controller 82 may direct a purging cycle, including one or more events,at a controlled duty cycle. For example, the purging cycle illustratedin table 118 in FIG. 5 may be implemented for 6 minutes after aregeneration cycle has ended. Then, purging of fuel injector unit 40and/or fuel supply circuit 48 may be implemented for 30 seconds, every 5minutes after the strategy illustrated in FIG. 5 has been implemented.Other implementations of a controlled duty cycle are contemplated to bewithin the scope of the disclosure.

Controller 82 may direct a purging cycle at a time sooner than otherwisescheduled and programmed where diagnostic devices monitoring pressureindicate that pressure from gas source 68, for example, may have beenbelow a predetermined minimum pressure, and thus too low during aprevious purging cycle for reliably sufficient purging. When such anindication occurs during a purging cycle, a pressure deficiency flag maybe initiated in controller 82 to adjust the timing for the next purgingcycle. This may occur, for example, where gas source 68 is a compressorfor a brake system of a machine, and the compressor was subjected toheavy demand by the brake system during a previous purging cycle.

Referring to FIGS. 1 and 2 in concert with FIGS. 3 and 4, a strategy maybe implemented for cleaning fuel supply system components, such as fuelinjector unit 40. As previously described, the exemplary cleaningsystems 84 and 102 illustrated in FIGS. 3 and 4, respectively, are notexclusive of the engine system and purging system illustrated in FIGS. 1and 2. The cleaning system of FIG. 3, or the cleaning system of FIG. 4,may be implemented in the system illustrated in FIGS. 1 and 2 at anysuitable position along gas flow path 70 between filter 72 andconnection to fuel injector unit 40 or fuel supply circuit 48, such as,for example, the position indicated by arrow 116.

In an exemplary embodiment wherein a cleaning system such as cleaningsystem 84 of FIG. 3 is implemented at exemplary position 116, a suitablecleaning strategy may be implemented. First, pressure gauge 94 may beinstalled at gauge port 96 in gas flow path 70, 70′. Once gauge 94 hasbeen installed, gas source 68, 68′, which may include an air pump, forexample, is activated for a time duration of 15 seconds. Once the 15second duration has elapsed, an operator may wait for gauge pressure todrop substantially to zero, indicating that line pressure has diminishedsufficiently to permit cleaning substance to be introduced.

When gauge pressure has reached substantially zero, an operator mayintroduce cleaning substance with, for example, a syringe or otherservice tool 86, capable of introducing a measured amount of cleaningsubstance. For example, 1.5 ounces of cleaning fluid may be introducedin a given cleaning cycle. After the cleaning fluid has been introduced,gas source 68 may be activated again for 15 seconds. By this strategy,fuel may first be purged from fuel injection unit 40, for example,cleaning fluid may then be introduced, and purging may once again occurto force cleaning fluid from lines leading to fuel injector unit 40 andthrough fuel injector unit 40, both to enhance cleaning and eliminatecleaning fluid and matter removed by the cleaning fluid from the linesand fuel injector unit 40.

In an exemplary embodiment wherein a cleaning system such as cleaningsystem 102 of FIG. 4 is implemented at exemplary position 116, asuitable cleaning strategy may be implemented. For example, after aregeneration cycle and a purge cycle (for example, a purge cycle similarto that of FIG. 5), controller 82, 82′ may activate metering valve 106via a suitable control line to introduce a measured amount, for example0.25 ounce, of cleaning fluid from supply container 104. Supplycontainer 104 may be, for example, an 18 ounce pressure container. Afterintroduction of this measured amount of cleaning fluid, controller 82,82′ may then activate gas source 68, 68″, which may be an air pump, fora duration of 15 seconds.

A system and method have been described that will facilitate cleaning afuel injector unit and associated components so as to eliminateundesirable deposits that accumulate due to the presence of fuel. Itwill be apparent to those having ordinary skill in the art that variousmodifications and variations can be made to the disclosed cleaningsystem and method without departing from the scope of the disclosure.

While exemplary embodiments have been disclosed in connection withcleaning fuel supply components, the disclosed system may be applicableto clean a liquid injection system in those exhaust aftertreatmentsystems that employ such a system. For example, the urea supply systemin a Selective Catalytic Reduction (SCR) system also may be subject todeposits in its associated liquid handling/injection system. Such asystem may benefit from a cleaning system implemented based on theteachings of this disclosure.

Other embodiments will be apparent to those having ordinary skill in theart from consideration of the specification and practice of thedisclosed embodiments. It is intended that the specification andexamples be considered as exemplary only with the true scope ofprotection being indicated by the following claims.

1. A method, comprising: operating a regeneration assembly to regeneratea filter assembly during a regeneration cycle; supplying fuel to atleast one fuel injector unit associated with the regeneration assemblyduring the regeneration cycle; dispensing a cleaning substance into afluid flow path associated with the regeneration assembly during acleaning cycle; and directing the cleaning substance through the atleast one fuel injector unit during the cleaning cycle.
 2. The method ofclaim 1, further including: dispensing the cleaning substance through aport in the fluid flow path with a service tool.
 3. The method of claim1, further including: prior to introducing the cleaning substance,pumping air through the fluid flow path and through the at least onefuel injector unit.
 4. The method of claim 3, further including:subsequent to introducing the cleaning substance, pumping air throughthe fluid flow path and through the at least one fuel injector unit. 5.The method of claim 4, wherein pumping air through the fluid flow pathand through the at least one fuel injector unit occurs for approximately15 seconds prior to dispensing the cleaning substance, and forapproximately 15 seconds subsequent to dispensing the cleaningsubstance.
 6. The method of claim 1, further including: activating anair pump via a controller to pump air trough the fluid flow path for ameasured time period before and/or after dispensing the cleaningsubstance.
 7. The method of claim 1, further including: measuringpressure within the fluid flow path; and dispensing the cleaningsubstance when the measured pressure is substantially zero.
 8. Themethod of claim 1, including dispensing the cleaning substance from apressure container through a metering valve.
 9. The method of claim 8,including activating the metering valve via a controller to dispense ameasured amount of cleaning substance.
 10. The method of claim 1,further including: monitoring at least one parameter indicative ofwhether fuel injection unit performance may benefit from dispensing acleaning substance; and dispensing the cleaning substance responsive tothe monitored parameter indicating fuel injector unit performance maybenefit from dispensing the cleaning substance.
 11. The method of claim1, further including: dispensing and directing the cleaning substance atprogrammed intervals.
 12. A system, comprising: a regeneration assemblyconfigured to regenerate a filter assembly during a regeneration cycle;a combustion chamber associated with the regeneration assembly; a fuelinjector unit for injecting fuel into the combustion chamber during theregeneration cycle; a gas flow path configured to communicate with thefuel injector unit; a gas source for selectively supplying gas throughthe gas flow path to the fuel injector unit; and an assembly fordispensing a cleaning substance into the gas flow path for cleaning thefuel injector unit during a cleaning cycle.
 13. The system of claim 12,wherein the assembly includes a port associated with the gas flow path,and a service tool providing a supply of cleaning substance andselectively connectible to the port.
 14. The system of claim 12, whereinthe gas source includes an air pump and the gas is air, and furtherincluding a filter for filtering air supplied by the air pump.
 15. Thesystem of claim 12, wherein the assembly includes a metering valve formetering a measured quantity of cleaning substance into the gas flowpath, and a supply container connectible to the metering valve toprovide a supply of cleaning substance.
 16. The system of claim 15,further including: a controller configured to activate the gas source tosupply gas for a predetermined time span before dispensing the cleaningsubstance, configured to activate the metering valve to introduce ameasured quantity of the cleaning substance, and configured to activatethe gas source to supply gas for a predetermined time span afterdispensing the cleaning substance.
 17. The system of claim 15, furtherincluding: a diagnostic device configured to monitor at least oneparameter indicative that the fuel injector unit may benefit fromintroduction of a cleaning substance; and a controller configured toreceive a signal from the diagnostic device and activate the meteringvalve to introduce a measured quantity of the cleaning substance inresponse to a signal indicating that the fuel injector unit may benefitfrom a cleaning cycle.
 18. A machine, comprising: an engine systemincluding an exhaust flow path; a filter assembly in the exhaust flowpath; a regeneration assembly proximate the exhaust flow path upstreamof the filter assembly, the regeneration assembly including a combustionchamber and configured to regenerate the filter assembly during aregeneration cycle; at least one fuel supply circuit and at least onefuel injector unit associated with the combustion chamber; and anassembly configured to dispense a cleaning substance to the at least onefuel injector unit.
 19. The machine of claim 18, wherein the machine isan on-highway truck.
 20. The machine of claim 18, wherein the assemblyconfigured to dispense a cleaning substance includes: a controllerconfigured to activate a metering valve to dispense the cleaningsubstance at least one of: after a predetermined number of regenerationcycles; and in response to a signal from at least one diagnostic devicemonitoring at least one parameter associated with fuel injector unitperformance.